Wednesday, January 17, 2018

Australia AHS layer update in the GeoGarage platform

10 nautical raster charts updated & 2 new charts added

New Zealand Linz update in the GeoGarage platform

3 nautical raster charts updated

A fantastical ship has set out to seek Malaysian Airlines flight 370

Norwegian research vessel Seabed Constructor
is one of the most advanced civilian exploration vessel on earth.

From The Economist 

A swarm of submarine drones will scour the depths for the plane

On January 2nd, at 8pm local time, a strange vessel cast off and sailed out of the Port of Durban, in South Africa, heading east.
Her hull was orange.
Her superstructure bristled with antennae—some long and pointy, some sleek, white and domed.
Her stern sported a crane and also a strange gantry, known to her crew as the “stinger”.
Her bow looked so huge and ungainly as to be on the point of tipping her, nose first, into the depths.
And below deck, invisible to those on shore, she carried eight autonomous submarines called HUGINs, each six metres long, weighing 1,800kg, and containing a titanium sphere to protect the sensitive electronics therein from the pressure of the ocean’s depths.

The strange ship’s name is Seabed Constructor.
She is a Norwegian research vessel, built in 2014 and owned by Swire Seabed, a dredging and surveying firm in Bergen.
At the moment, though, she is leased to Ocean Infinity, a company based in Houston, Texas.
And the task Ocean Infinity has hired her for is a hard one: to find whatever is left of flight MH370, a Boeing 777-200ER that left Kuala Lumpur on March 8th 2014 with 239 people on board and vanished over the Indian Ocean.

The disappearance of MH370 is one of the great mysteries of modern civil aviation.
The aircraft was bound for Beijing, but changed course suddenly over the South China Sea and broke off radio contact.
It was last detected by radar near the northern tip of Sumatra, heading west-north-west into the open ocean.
Subsequent transmissions to a communications satellite suggested that it crashed somewhere along an arc between 1,500km and 2,700km west of Australia.


The search that followed was the largest in aviation history.
It was mounted by Fugro, a Dutch firm, and paid for by the Malaysian, Chinese and Australian governments.
Over the course of three years Fugro managed to scan 120,000 square kilometres of seabed.
But it found nothing.
The plan is for Ocean Infinity’s search to be paid for, on a “no find, no fee” basis, by Malaysia alone.
Contracts have yet to be signed, but Oliver Plunkett, Ocean Infinity’s boss, has decided to go ahead anyway, to take advantage of the window of good weather that opens in the southern Indian Ocean in January and February.

 Increased-resolution Bathymetry in the Southeast Indian Ocean

Ocean Infinity aims to cover the ground much faster than Fugro did.
In prior cruises in the Atlantic, the firm has, according to Josh Broussard, its technical director, managed to scan 890 square kilometres a day using six autonomous submarines.
With eight, Mr Broussard thinks that the new mission will be able to manage 1,200 a day—enough to have covered the original search area in just 100 days.

The new search area, 25,000 square kilometres of sea floor chosen by investigators from the Australian Transport Safety Bureau (ATSB), is just north of the old one (see map).
Fugro could infer MH370’s crash site only from its final, rather shaky, satellite signals.
Ocean Infinity’s effort has been guided as well by wreckage washed ashore on the coasts of Africa and several islands in the Indian Ocean—hence the more northerly starting point.
Seabed Constructor will reach that starting-point, which is about 35°S, and 2,200km off the coast of Western Australia, on or about January 17th, her crew having conducted a few final tests and calibrations of the HUGIN system en route, using remote-controlled robots to place dummy debris on the sea floor in order to see if the subs can find it.
If searching the patch of ocean designated by the ATSB reveals nothing, then the ship will head farther north, towards the 30th parallel, which some independent experts believe is a better bet.

 
An ocean of interest


Fugro’s search used but a single autonomous submarine, and this was unable to dive below 4,000 metres, meaning it was not always close to the seabed.
The HUGINs carried by Seabed Constructor can, however, go as deep as 6,000 metres.
That permits them to reach most of the sea floor comfortably.
And the fact that there are eight of them means different areas can be searched in parallel, and that some submarines will always be at sea.

The HUGINs will be launched by the stinger, which extends out over the ship’s stern.
Once underwater, the robot craft will communicate with the ship using an acoustic modem.
The ship’s own modem, which will receive these signals, is fixed to the end of a long pole that extends down through her hull into the water.

Each HUGIN comes with a 300kg lithium-polymer battery pack, good for a tour of duty lasting up to 60 hours.
A downward-pointing sonar will map the contours of the seabed beneath the craft, but most of the searching will be done by side-mounted sonars scanning the bed on either side of the craft.
These send out pings and measure the intensity with which they are reflected.
Sand reflects less sound than metal does, meaning metal objects such as aircraft debris are easy to distinguish.
And if something apparently metallic is detected, its nature can be confirmed using an on-board magnetometer.

 Video describing the capabilities of the Kongsberg Maritime Hugin Autonomous Underwater Vehicle

The HUGINs’ search patterns are set by people, but the craft will actually navigate with little reference to their mother ship.
Every so often, the ship will send out a corrective ping to keep them on course.
Mostly, however, they will employ dead reckoning, based on data from accelerometers, to steer themselves autonomously.
They are also capable of picking their way without assistance over sheer underwater cliffs and mountains, and past crevices and gullies, using on-board cameras and machine-vision software.

After its tour of duty, a HUGIN will be lifted back on-board ship and the data it has collected (up to two terabytes, recorded on a waterproof hard drive) downloaded into the ship’s data centre and turned into human-readable maps, a process that takes six hours.
The HUGIN’s battery will be replaced with a fully charged one, any necessary repairs made, and the craft then sent back out into the ocean.


 Video describing the launch and recovery system of the Kongsberg Maritime Hugin Autonomous Underwater Vehicle
 
A team of geologists and hydrographers will then pore over the maps, looking for signs of the missing plane.
Surprisingly, for such a high-tech operation, this stage of the search will be entirely manual.
Every block of sea floor that the HUGINs map will be examined by three sets of human eyes.
Together, this survey team will come up with a list of possible targets, ranked from “E” to “A” (“nothing” to “that’s it”), to present to their bosses.
If the data look good, a HUGIN will be sent down for a second, closer look, cameras at the ready.

What happens next, if Ocean Infinity does locate what is left of the missing aircraft, is unclear.
Friends and relatives of those aboard it will doubtless derive relief from knowing where the flight ended up.
But merely finding the wreckage will not explain what happened on board the plane.
That will require the discovery of the aircraft’s flight recorder.

That object is therefore Ocean Infinity’s ultimate target.
If it is found on this mission, Mr Broussard says the firm plans to bring it to the surface and then deliver it for analysis to the Australian authorities, who have the technical competence to assess it.
A follow-up trip to examine the wreckage, and even bring it to the surface, would require further authorisation from the Malaysian government.

Seabed Constructor is the most advanced civilian survey vessel on the planet today.
If its array of technology cannot find MH370, then it is likely that nothing will, and that the mystery of MH370 will remain unsolved.
Either way, though, the advance of technology may mean that it is the last such mystery.
As the oceans are watched with ever closer scrutiny, from space and the depths, it is increasingly difficult for anything to get lost in the first place.

Links :

Tuesday, January 16, 2018

Huge oil spill spreads in East China Sea, stirring environmental fears

A collision involving the Sanchi — shown being doused at right before it sank — created what appeared to be the largest tanker oil spill since 1991.
Environmentalists and marine experts are concerned about the oil slick’s threat to sea and bird life in the East China Sea.
CreditTransport Ministry of China, via European Pressphoto Agency

From NYTimes by Gerry Mullany

An oil spill from an Iranian tanker that sank in the East China Sea is rapidly spreading, officials said Tuesday, alarming environmentalists about the threat to sea and bird life in the waterway.


The tanker, the Sanchi, was carrying 136,000 tons of highly flammable fuel oil when it crashed into a freighter on Jan. 6.
On Sunday, the Sanchi sank after a huge blast sent up a great plume of black smoke and set the surface of the water on fire, China Central Television said.

The bodies of three crew members have been recovered, and the remaining 29 were presumed dead, the Iranian government said.
Thirty Iranians and two Bangladeshis were believed to have died.

 The burning Iranian oil tanker Sanchi is seen partially sunk in the East China Sea
off the eastern coast of China on January 14.

The oil slicks from the sunken tanker were growing in size, China’s State Oceanic Administration said Tuesday.
There are now two huge slicks covering 52 square miles, compared with just four square miles the previous day.
Strong winds were pushing the spill toward Japan, away from China, and it was now less than 200 miles from Naha, Japan.

One concern is that, since the Sanchi sank, marine life will be endangered by the fuel oil’s spreading instead of burning off.
And experts are further concerned that the even dirtier bunker fuel powering the tanker will be released into the sea, exposing delicate marine life to the extremely toxic substance.

Greenpeace expressed alarm about the threat to the marine ecosystem in the East China Sea, which is one of the world’s most heavily trafficked waterways, saying the disaster occurred in “an important spawning ground” for fish.
“At this time of year the area is used as wintering ground by common edible species such as hairtail, yellow croaker, chub mackerel and blue crab,” Greenpeace said.
“The area is also on the migratory pathway of many marine mammals, such as humpback whale, right whale and gray whale.”

The tanker was carrying more than one million barrels of condensate, an extremely light crude oil, to South Korea when it collided with the freighter.
When spilled, the condensate can produce a deep underwater plume damaging to marine life.

File photo shows a rescue ship sailing near the burning Iranian oil tanker Sanchi
photo AP

The Japanese Coast Guard said the fire on the surface of the sea was extinguished early Monday.

The Sanchi disaster appears to be the largest tanker spill since 1991, when an unexplained detonation caused the ABT tanker to leak 260,000 tons of oil off the coast of Angola.

Rick Steiner, a marine conservation specialist formerly with the University of Alaska, told The Associated Press that 60,000 to 90,000 tons was likely to have spilled into the sea, calling it “enormous” and “as large as the official estimate of the Exxon Valdez disaster” off the coast of Alaska in 1989.
He also suggested that the Chinese government was likely to be understating the magnitude of the spill.
Hiroshi Takahashi, a fisheries official in Kagoshima Prefecture in Japan, said the government was “monitoring the direction” of the spill because of fears it “could direct towards Kagoshima.”

The deaths of the Iranian crew members on the tanker prompted Iran’s government to declare a day of national mourning on Monday to honor “the brave mariners who died in the course of their mission.”

Eshaq Jahangiri, Iran’s first vice president, said that efforts to recover the bodies of 29 crew members ceased when the tanker sank off the China’s coast on Sunday.

Because of the release of toxic gases in the immediate aftermath of the explosion, there was little hope that the crew members survived, but efforts to recover their bodies had continued, Mr. Jahangiri said.
“Unfortunately, the ship sank and we could not access their bodies.”

 A computer-generated scenario of where the slick will spread.
(Image: National Oceanography Centre)

Officials still don’t know the cause of the collision between the Sanchi and the CF Crystal, a Chinese freighter that was carrying grain.

Links :

Monday, January 15, 2018

US NOAA layer update in the GeoGarage platform

3 nautical raster charts updated

Is fishing with electricity less destructive than digging up the seabed with beam trawlers?


The pulse trawl: electrodes in the two direction of the gear cause an electric field above the seabed, which stimulate the flatfish so that come up and end up in the net

From The Conversation by Michel Kaiser

While many people may be interested in the sustainability and welfare of the fish they eat, or the health of the environment, fewer probably worry about the effect that trawl fishing – which accounts for 20% of landings – has on the ocean.

For a long time researchers and the industry have been trying to improve trawl fishing practices.
Things have moved on from practices such as beam trawling – where a large net is dragged across the ocean floor – to potentially less invasive and newer methods like electric pulse trawling.
This sees electrical pulses being sent into the seawater to flush out bottom-dwelling fish like plaice and sole, causing them to swim into the path of trawl nets.


Beam trawls have been the focus of environmental concern for decades, as it causes a substantial reduction in the abundance of animals living on the seabed.
These effects can be long lasting if the fishing occurs in areas which are inhabited by long-lived seabed dwelling species such as oysters and sponges.
Beam trawls are also associated with high amounts of bycatch – unwanted fish and other organisms – although the industry and researchers are working on ways to reduce this.

However, the relatively newer electric pulse fishing is not necessarily a perfect solution either.
Though it does not dig into the seabed to the same extent as traditional beam trawling, research has found it can fatally injure other species which may not be the target catch.

So why use this method if it still has its faults?
High fuel costs and EU legislation which has reduced the discarding fish at sea, have renewed interest in the use of electricity in fishing.
Across the world, millions are fed by the fish caught by trawlers so it is unrealistic for trawling to just be stopped altogether, but the variety of negative impacts on the marine ecosystem remain a cause for concern.

 courtesy of WUR / illustration Justin Tiand

For and against

The UK government recently announced an review into the use of electric pulses by foreign trawlers in British waters due to concerns about its potential effects on the environment and bycatch.
Campaign groups have also called on the EU to reinstate a ban on the electrical pulse method, calling it “destructive”.

The current pulse trawls are fine-tuned to catch larger fish (the spine of the fish acts as a conductor), so that bigger fish respond more strongly to the electric stimulus and are more likely to be caught in the nets.
This reduces catch of unwanted species that are less likely to respond to the electric pulse, and also reduces contact with the seabed.

Traditional beam trawls, on the other hand, are fitted with heavy “tickler chains” – horizontal chains strung across the mouth of the trawl – designed to “dig” fish like Dover sole out of the seabed.
Soles curl into a “c” shape in response to the electric stimulation used by pulse trawls, so they can be caught without the use of these “tickler chains”.

 courtesy of Pulse Fishing

Dispensing with the chains means that the gear is lighter, creates less disruption of the seabed, and substantially reduces the amount of other seabed organisms caught – by 75-80% per unit area of the seabed fished.
By not catching the unwanted species, this improves the quality of landed catch too, because skin abrasion is reduced in the net.
Together, improved catch quality and the reduced fuel consumption means greater profitability for the fishermen.

Electric pulse seems like a good idea from this perspective, but studies of its effects on other species of fish – that are not the intended catch – show that larger cod in particular are prone to spinal fractures when in contact with the electric pulses.
Small cod appear to be unaffected.
Cod typically have a low survival rate if they are unintentionally caught in most trawls, so this issue of spinal fracture may be irrelevant if they are caught using either method.


Additionally, though fewer seabed organisms end up in the trawl net when using electricity compared to traditional beam trawling, it is too early to tell whether the creatures remaining on the seabed are affected negatively by contact with the electric stimuli.
Aquarium experiments, have shown that worms and shrimps, for example, recover within seconds following the application of an electric shock.
However, these controlled laboratory experiments take place without natural predators – that may take advantage of a shocked creature – present.

The issues here are not solely environmental.
The pulse trawl fleet has encroached on grounds that historically were fished by fishermen using low impact netting methods, leading to some resentment and conflict with others in the fishing community.

Societal acceptance of any food production method is vital, and at present – for pulse trawling – this is a greater challenge than answering the ecological questions.
This issue could be resolved by more formal zoning of the sea so that pulse trawling is restricted to areas that do not impinge upon traditional low impact fisheries – initiatives which are currently in negotiation.

Taking both society and environment into account, electric pulse trawling may not be an infallible solution, but it might a better way of trawling than the use of traditional forms of beam trawling.

Links :


Saturday, January 13, 2018

Antiques road trip at UKHO


In this clip, antiques expert James Braxton visits the United Kingdom Hydrographic Office (UKHO) in Taunton, Somerset
A nice trip down memory lane ending with the most modern methods of hydrographic survey

Links :

Northwest Passage : a family adventure


This video is about KAMANA NWP Eastbound in 2017
'Plum' sailing boat, Solaris 72 21,55 m (skipper Enrico Tettamanti)
crew 12 persons (5 children)

Friday, January 12, 2018

Giant 'Blue Hole' found in Great Barrier Reef by marine biologist

According to new satellite imagery of the area, a giant blue hole was recently discovered within Australia's Great Barrier Reef.
Marine biologist Johnny Gaskell who has since explored the spot, said,
"What we found inside was hard to believe considering 5 months ago a Category 4 cyclone went straight over the top of it."
According to Gaskell, pristine colonies of giant birdsnest corals and extremely long Staghorn corals found in the "blue hole," were completely unaffected by Cyclone Debbie, which slammed into the region as a Category 4 storm back in late March.

From Johnny Gaskell

Blue Hole mission in the Great Barrier Reef.
This Blue Hole has previously been explored and documented by geologists who suggested it could be even older than the famous Great Blue Hole, in Belize.
It's location is in one of the least explored parts Great Barrier Reef, over 200km from our home @daydreamislandresort.

Gaskell began searching for blue holes in March last year after Cyclone Debbie hit, in hope of finding coral that was spared from the storm.
The high walls that line the sinkholes tend to preserve what lies below from damaging weather. Large hurricanes can be particularly dangerous for corals, as they are smashed by swells.
The blue hole that Gaskell spotted on Google Maps was in a remote location, nearly 190 kilometres away from the nearest island.
While the specific blue hole had been previously identified, its remoteness made it difficult to access and little was known about it.
Gaskell was able to finally confirm that it was a blue hole during the diving expedition in September.

The majority of blue holes are formed from sinkholes or caves that develop slowly over time, as rock begins to erode and collapse.
Many of the world’s blue holes formed during the last Ice Age, after sea levels rose and filled existing sinkholes with water.
The term blue hole simply comes from the dark, navy waters that characterise the formations, often creating a striking contrast with the turquoise that surrounds them.

 “This Blue Hole has previously been explored and documented by geologists who suggested it could be even older than the famous Great Blue Hole, in Belize."
pictures : Johnny Gaskell 

To get there we had to travel overnight for 10 hours and time the tides perfectly...
Was well worth it! Inside the walls was similar to the site we explored a few weeks back, but this hole was deeper and almost perfectly circular.
We dived down to just over 20m yesterday, before hitting bare sediment, that slowly sloped towards the centre.
Again it was great to see big healthy coral colonies.

“Due to the sediment build-up over thousands of years, blue holes can be like time capsules for the ocean,” Gaskell said. 

We call it 'The Crack'....
Up there with the most ultimate snorkels I've ever done...

“At around 15 to 20 meters deep, there were huge Birdsnest Corals (Seriatopora) and super elongated Staghorn Corals (Acropora), both of which were among the biggest and most delicate colonies I’ve ever seen,” Mr Gaskell said.
 
After diving the Blue Hole over the weekend, we decided to move sites and check out what looked like a huge crack in the reef
 Open to the ocean at one end, and closed in by Reef at the other.
The total length was over a 1Km long, about 50m wide and the depth is still unknown.



The strong current along the walls meant we had to drift the whole way.
This video doesn't do the site justice as most of the bigger inhabitants were not keen to come close. Only filmed fish and corals at the top on the edges.
Freediving into the depths we saw Grey Reef Sharks, Whitetip Reef sharks, Maori Wrasse, a Tawny Nurse and a 3m Lemon shark.
Seeing a huge school of Humpnose Unicornfish was definitely my highlight.
Counted over 100 in one photo.

Want to know exactly where it is? Sorry, it's still a secret.
The blue hole sits in the heart of the Great Barrier Reef off the Whitsunday Coast.
“Its location is in one of the least explored parts Great Barrier Reef, over 200 km from Daydream Island. "
Gaskell however, hasn't revealed the exact location of his discovery, so it remains a new and local secret...
"Hopefully it will be left alone.
An influx of divers would severely damage the coral colonies, as they are more delicate than usual."
Picture : nautical charts (Australia AHS) overlaid upon Google Maps imagery in the GeoGarage platform webmapping.

It's a long way offshore this spot, but hopefully we'll get back there one day.
The Crack...

 Example of another Blue Hole in the GBR found in the GeoGarage platform ?
There are a couple of known blue holes in Australia but they are quite unexplored and due to the sheer size of the Great Barrier Reef, its certain that more are out there.
Wonky Hole is 80 metres (262 feet) deep and an amazing dive teaming with sea life and covered in whip coral and gorgonians.
The Barrier Star is another hole dropping to 90 metres (295 feet) with an overhang at the sandy bottom and an abundance of reef life and coral.

Gaskell plans to continue looking for and surveying blue holes in the Great Barrier Reef.
“Some of these sites have had scientists explore them in the past, but due to the remote offshore location, there are still parts of the Great Barrier Reef that remain a mystery,” he said.

Links :

Thursday, January 11, 2018

What makes Russia’s new spy ship Yantar special?

The Yantar seen in the Bosphorus en route to Syria in 2017 
(photo Yoruk Isik)

From BBC by Laurence Peter

The Russian navy is very proud of its new spy ship, the Yantar, which is now doing Argentina a favour by helping to search for a missing submarine.

Argentina has given up trying to rescue the 44 crew aboard the ARA San Juan, which disappeared on 15 November.
But it still wants to find the diesel-electric submarine.

 Yantar ship

Enter the Yantar, officially an oceanographic research vessel, but actually bristling with surveillance equipment, and the mother ship for manned and unmanned deep-sea submersibles.
A Russian ROV - remotely operated underwater vehicle - is scouring the ocean floor off Argentina.
 
The disappearance of the ARA San Juan remains a mystery
photo Reuters

But what else has the Yantar (Russian for "amber") been up to?

Targeting undersea cables

The Yantar's movements were apparently what prompted a warning last month from the UK military that Russia could disrupt or cut vital undersea communications cables.
The chief of the UK defence staff, Air Chief Marshal Sir Stuart Peach, said such a strike against internet and other communications cables could be "catastrophic".
Dozens of fibre-optic cables span the globe and Nato also has dedicated military cables on the ocean floor.


The Yantar is capable of tampering with them, says Igor Sutyagin, a London-based expert on the Russian military.
But there is no evidence that it has done so.
"It's difficult to tap into optical fibres - it's just light inside, not electrical data," he told the BBC.
"It would be easier just to cut the cable."

Mr Sutyagin noted that in the 1970s, during the Cold War, the US Navy had lost control of a Sosus undersea listening post for tracking submarines in the Atlantic.
Sosus stands for "Sound Surveillance System".
The US military concluded that a Soviet submarine had cut the cables.
In the same period the US military, reports say, planted listening devices on Soviet undersea cables in the Sea of Okhotsk, where Soviet submarines were based.

A news report from the Russian parliament says the Yantar can do just such clandestine work, using deep-diving submersibles.
"The Yantar has equipment designed for deep-sea tracking, and devices that can connect to top-secret communications cables," said Parlamentskaya Gazeta (in Russian) last October.
Mr Sutyagin, of the Royal United Services Institute, says the Yantar belongs to Russia's Main Directorate of Underwater Research (GUGI in Russian), part of the defence ministry.

The 108m-long (354ft) vessel has a crew of 60 and went into service in 2015.
It was built in the Baltic port of Kaliningrad, the first in a series called Project 22010.
A second, called Almaz, will soon be on its way to the navy.

Russia already has several older spy ships.
In April, one of them, the Liman, sank off the Turkish coast after being breached in a collision with a freighter.
All its crew were rescued.

The Yantar can deploy the three-man submersibles Rus and Konsul, which can dive to about 6,000m (20,000ft).
The Rus submersible has a crew of three and dived to 6,180m in the Atlantic

 The Rus submersible has a crew of three and dived to 6,180m in the Atlantic 
photo Russian Defence Ministry

Spying on the US

The Russian parliamentary report noted that in the summer of 2015 the Yantar had deployed near the US Kings Bay naval base in Georgia.
"According to Pentagon officials, the Russians were gathering intelligence on US submarines' equipment, including underwater sensors in the DoDIN network," the Russian report said.
Mr Sutyagin said the US underwater sensors near Kings Bay would be interesting for the Russian military, which might wish to copy the US technology.

In late 2016 the Yantar was found to be loitering over undersea communications cables off the Syrian coast, including some links to Europe.
The Yantar's frequent stops at points along a cable route suggested that a submersible was examining the sea floor, the report said.



 According to Argentina's Navy document,
the last known position of the ship on November 15 was 46°44 ‘ south, 59°54’ west.
Mystery of ARA San Juan
Search and rescue

Besides the Argentina mission, the Yantar has been used previously for search and recovery.
The Russian parliamentary report said the ship had located two Russian fighter jets - a Su-33 and a MiG-29 - that crashed into the Mediterranean in 2016, during the Syria war.
The Yantar "recovered secret equipment from the planes in good time", the report said.
That could be secret radar or missile data, or the "identification, friend or foe" system, Mr Sutyagin said.

In 2000 a ship like the Yantar might have saved some Kursk sailors' lives and literally salvaged the Russian navy's reputation.

Links :

Wednesday, January 10, 2018

The bottom of the ocean is sinking

Satellite data enables scientists to map the seafloor, which is sinking under the weight of rising seas. (This map shows gravity anomalies in the western Indian Ocean.)
Credit: NASA Earth Observatory

From Live Science by Mindy Weidberger

The bottom of the ocean is more of a "sunken place" than it used to be.

In recent decades, melting ice sheets and glaciers driven by climate change are swelling Earth's oceans.
And along with all that water comes an unexpected consequence — the weight of the additional liquid is pressing down on the seafloor, causing it to sink.

 Modeled barystatic contributions and definition of the individual ocean basins.
(a) Time series of the modeled barystatic sea level changes from each individual process and their sum. The shaded areas show the 1σ confidence interval. 
b) Definition of each ocean basin. The dots show the tide gauge locations, and the color the basin to which each tide gauge is linked. The black lines show the upper and lower bounds of the altimetry domain.

Consequently, measurements and predictions of sea-level rise may have been incorrect since 1993, underestimating the growing volume of water in the oceans due to the receding bottom, according to a new study.

The 275 trillion pounds of water from Hurricane Harvey deformed the ground in Texas.

The weight of Harvey's water pushed Houston down
Scientists have long known that Earth's crust, or outer layer, is elastic: Earlier research revealed how Earth's surface warps in response to tidal movements that redistribute masses of water; and 2017's Hurricane Harvey dumped so much water on Texas that the ground dropped 0.8 inches (2 centimeters), the Atlantic reported.

 Linear trends and accompanying 1σ confidence intervals resulting from ice mass and LWS changes over 1993–2014 in (a) solid Earth deformation over the oceans, (b) relative sea level, and (c) geocentric sea level.
Note that geocentric sea level change is equivalent to the sum of relative sea level and ocean bottom deformation change.
The blue line depicts the line where local sea level change is equal to the ocean mean sea level trend, whose value is written in blue under each map.

In the new investigation, researchers looked at more long-term impacts to the seafloor.
They evaluated how much the shape of the ocean bottom may have changed between 1993 and 2014, taking into account the amount of water added to the ocean from liquid formerly locked up on land as ice.
Previous research into seafloor stretching had omitted that extra water, the scientists wrote in the study.


To do that, they reviewed approximations of mass loss on land, as ice melted and drained into the oceans, and compared that to estimates of sea volume changes.
They found that around the world for two decades, ocean basins deformed an average of 0.004 inches (0.1 millimeter) per year, with a total deformation of 0.08 inches (2 mm).

However, there were distinct regional patterns to the seafloor's bending and stretching, and the amount of sag in certain parts of the ocean bottom could be significantly higher — as much as 0.04 inches (1 mm) per year in the Arctic Ocean, for a total of 0.8 inches (20 mm), the study authors reported.

 Basin-averaged and global mean effects of present-day mass redistribution on observed relative and geocentric sea level change.
The solid line represents the average spatial signal over each region.
The dashed line (“TG rec”) represents tide gauge reconstructions based on the virtual station method using the locations of the 627 PSMSL tide gauges.
The altimetry domain consists of the global oceans, bounded by ±66∘ latitude.
For the virtual station estimate of the altimetry domain, all regions except the Arctic Ocean region are used.

As a result, satellite assessments of sea-level change — which don't account for a sinking ocean bottom — could be underestimating the amount that seas are rising by 8 percent, according to the study.

The accuracy of future sea-level estimates could be notably improved if the sinking of the ocean floor were incorporated into the calculations, "either based on modeled estimates of ocean mass change, as was done in this study, or using more direct observations," the scientists concluded.

The findings were published online Dec. 23 in the journal Geophysical Research Letters.

Links :



Tuesday, January 9, 2018

Coral reef bleaching 'the new normal' and a fatal threat to ecosystems

Coral bleaching on the Great Barrief Reef.
While mass bleaching events used to occur once every 27 years, by 2016 the median time between them was 5.9 years.
Photograph: Greg Torda/ARC Centre of Excellence for Coral Reef Studies

From The Guardian by Helen Davidson

Study of 100 tropical reef locations finds time between bleaching events has shrunk and is too short for full recovery

Repeated large-scale coral bleaching events are the new normal thanks to global warming, a team of international scientists has found.
In a study published in the journal Science, the researchers revealed a “dramatic shortening” of the time between bleaching events was “threatening the future existence of these iconic ecosystems and the livelihoods of many millions of people”.

Did you know there’s coral in Scottish waters?
Discover how a barren seabed transformed into a vibrant seascape

The study examined 100 tropical reef locations across the world, analysing existing data on coral bleaching events as well as new field research conducted on the Great Barrier Reef after the longest and worst case of bleaching caused by climate change killed almost 25% of the coral.
“Before the 1980s, mass bleaching of corals was unheard of, even during strong El Niño conditions,” said lead author Prof Terry Hughes, director of the ARC Centre of Excellence for Coral Reef Studies. “Now repeated bouts of regional-scale bleaching and mass mortality of corals has become the new normal around the world as temperatures continue to rise.”


The study found that time between bleaching events had diminished five-fold in the past 30 to 40 years, and was now too short to allow for a full recovery and was approaching unsustainable levels.
While mass bleaching events used to occur about once every 27 years, by 2016 the median time between them had shrunk to 5.9 years.
Only six of the 100 sites had escaped bleaching.
“Our analysis indicates that we are already approaching a scenario in which every hot summer, with or without an El Niño event, has the potential to cause bleaching and mortality at a regional scale,” the paper said.

Globally, the annual risk of severe and moderate bleaching had increased by almost 4% a year since the 1980s, from an expected 8% of locations to 31% in 2016.
The Western Atlantic remained at highest risk but Australasia and the Middle East saw the strongest increases in risk of bleaching.


This video shows the intricate details of small coral polyps, which contract and expand after disturbances, in stunning 4K quality.

Hughes said he hoped the “stark results” would prompt stronger action on reducing greenhouse gases.
In May scientists warned that the central goal of the Australian government’s protection plan was no longer feasible because of the dramatic impact of climate change.

Friday’s paper also determined the link between El Niño and mass bleaching events has diminished as global warming continues.
Prior to the 1980s mass coral bleaching on a regional scale was “exceedingly rare or absent” and occurred in localised areas stretching tens of kilometres, not the hundreds of kilometres affected in recent times, the paper said.
These local bleaching events were largely caused by small-scale stressors like unusually hot or cold weather, freshwater inundation or sedimentation.

Then global warming increased the thermal stress of strong El Niño events, the paper said, widening the impact of individual bleaching events. Now, they are occurring at any time.
“Back in the 80s it was only during El Niño events that waters became hot enough to damage corals and induce them to bleach,” co-author Andrew Baird, a professor at James Cook University, told Guardian Australia.
“But now it’s 30, 40 years later and we’re seeing those temperatures in normal years.”
Baird said it was difficult to know if the current conditions were reversible but “the window to address it is diminishing”.
“It’s impossible to know if this is the end of coral reefs but it might be,” he said.
“We really need to get on top of climate change as soon as possible.”

The vaults of the largest coral sperm bank in the the work may one day hold the key to saving ocean life.

There have been several large-scale and devastating mass bleaching events in recent years.
The 2015-16 event affected 75% of the reefs studied by the researchers, who said it was comparable to the then unprecedented mass bleaching of 1997-98, when 74% were affected.
“Interestingly one of the first papers that effectively drew attention to the issue – back in 1999 – suggested that by 2016, 2017, 2020, we would be seeing bleaching annually,” Baird said.
“That’s pretty close to what’s happening unfortunately.
“Some of these earlier works were quite prescient in their prediction and unfortunately we didn’t pay enough attention back then.”

The study follows a discovery late last year that 3% of the Great Barrier Reef could facilitate recovery after bleaching – a finding the researchers at the time suggested was akin to a life-support system but small enough not to be taken for granted.
On Friday scientists announced that a major outbreak of coral-eating crown of thorns starfish had been found munching the Great Barrier Reef in December, prompting the Australian government to begin culling the spiky marine animals.


The predator starfish feeds on corals by spreading its stomach over them and using digestive enzymes to liquefy tissue.
“Each starfish eats about its body diameter a night, and so over time that mounts up very significantly,” Hugh Sweatman, a senior research scientist at the Australian Institute of Marine Science told ABC radio.
“A lot of coral will be lost,” he said.

The crown of thorns were found in plague proportions in the Swains reefs, at the southern edge of the Great Barrier Reef, by researchers from the Great Barrier Reef Marine Park Authority.
The authority already killed some starfish at Swains reefs in December and said it would mount another mission in January.

There have been four major crown of thorns outbreaks since the 1960s in the Great Barrier Reef but it recovered each time because there were always healthy populations of herbivorous fish. The outbreaks are usually triggered by extra nutrients in the water but the reason for the current outbreak was unclear, Sweatman said.

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Monday, January 8, 2018

Canada CHS layer update in the GeoGarage platform

67 nautical raster charts updated

Mediterranean Sea Rescue

courtesy of Migrants at sea blog

From GoogleMapsMania by Keir Clarke

In the last three years Médecins Sans Frontières (MSF) has carried out nearly 400 search and rescue operations in the Mediterranean Sea.
Every year thousands of refugees, many fleeing from violence, war, persecution and poverty in Sub-Saharan Africa, drown while trying to reach Europe via the Mediterranean. MSF has saved thousands of other refugees from suffering the same fate.

The MSF Search and Rescue interactive map shows the locations of all of MSF's rescues in the Mediterranean since 2014.
The majority of these sea rescues have taken place off the coast of Libya.
The MSF says that "almost everyone rescued from this stretch of water has passed through Libya, where many of them have been exposed to alarming levels of violence and exploitation".


More than 5,000 refugees died in 2016 trying to get to Europe across the Mediterranean Sea. Crossing the Mediterranean Sea by Boat - Mapping and Documenting Migratory Journeys and Experiences is an international research project, led by the University of Warwick, which carried out 257 in-depth qualitative interviews with people who have made this journey.

The project has released an interactive story map which allows you to view some of these migratory journeys on a map, while also learning about the individual experiences of the people who actually made the journeys.


Each of these individual journeys are mapped to show each stage of one refugee's migration from Africa to Europe.
'Back' and 'Next' buttons allow the user to follow each stage of the journey made by the interviewed refugees.
As the map updates the map side-panel also updates to provide information about the journey.
This information includes the first-hand experiences of the individual refugee and more general information about the conditions that refugees experience at the mapped locations.


15 Years: Fortress Europe is an animated map of migrant and refugee deaths in Europe over the last fifteen years.
The map uses data from the Migrant Files to show where and when migrants have died while trying to get to Europe, or while trying to move around the continent.

As the map plays through the fifteen years of data red markers are added to the map to show the location of each migrant death.
The map sidebar continually updates to show details about each migrant death and you can click on individual markers on the map to read more details about each of these deaths.

Since 2013 the Migrant Files has been maintaining a database of migrants who have died in Europe or on their way to Europe.
The database lists more than 30,000 people who have died trying to get to Europe since the year 2000.

An interactive map on the Migrant Files website shows that a large proportion of these deaths occur in the Mediterranean, particularly among migrants trying to cross from Libya & Tunisia to Italy.


The Silk team has also created an interactive map from the Migrants' Files data examining the number of migrant deaths in the Mediterranean.
Their map allows you to query the information about migrant deaths by year, location and cause of death.

If you click on a map marker on the Fatal Migration Incidents in the Mediterranean map you can read details about the mapped incident, including the number of casualties and the date of the incident.


The Migrant Map 2000-2015 is another interactive map of the Migrant Files data, visualizing the number of dead or missing migrants across Europe and Africa.
The map presents a truly shocking picture of the scale of this human tragedy.

You can select markers on the map to learn more about the individual cases reported and about the source of the information.
The map also includes an animated heat-map layer which helps to highlight some of the hot-spots for migrant deaths over the last six years.

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Saturday, January 6, 2018

Slurpee waves return to Nantucket


Photographer Jonathan Nimerfroh captured the rare Slurpee Wave natural phenomena off Nantucket, MA once again at Nobadeer Beach on Jan. 2, 2018.

The natural phenomena that has hit the island of Nantucket the past few winters due to freezing cold temperatures has struck again.
That’s right, the Slurpee Wave is back in 2018 and photographer Jonathan Nimerfroh was there again to document the icy waves.

The air temperature was 12-degrees while the ocean was a balmy 36 on this particular day, which both lend themselves to some ice formation.
Keep in mind, this is the ocean, not fresh water like those photos you see from the Great Lakes with the crazy ice beards -- salt water freezes at a much lower temperature than fresh water.
“It’s not that bad once you get in there,” Jamie Briard said after getting out from the slushy waters.
“I’ve never done anything like that,” Nick Hayden says after getting out, icicles formed on both of them.
“I could see my fins slicing through the slush.”

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Friday, January 5, 2018

Oceans suffocating as huge dead zones quadruple since 1950, scientists warn

 A fisherman on a beach in Temuco, Chile that is blanketed with dead sardines, a result of algal blooms that suck oxygen out of the water.
Photograph: Felix Marquez/AP

From The Guardian by Damian Carrington

Areas starved of oxygen in open ocean and by coasts have soared in recent decades, risking dire consequences for marine life and humanity

Ocean dead zones with zero oxygen have quadrupled in size since 1950, scientists have warned, while the number of very low oxygen sites near coasts have multiplied tenfold.
Most sea creatures cannot survive in these zones and current trends would lead to mass extinction in the long run, risking dire consequences for the hundreds of millions of people who depend on the sea.

Climate change caused by fossil fuel burning is the cause of the large-scale deoxygenation, as warmer waters hold less oxygen.
The coastal dead zones result from fertiliser and sewage running off the land and into the seas.

The analysis, published in the journal Science, is the first comprehensive analysis of the areas and states: “Major extinction events in Earth’s history have been associated with warm climates and oxygen-deficient oceans.”
Denise Breitburg, at the Smithsonian Environmental Research Center in the US and who led the analysis, said: “Under the current trajectory that is where we would be headed. But the consequences to humans of staying on that trajectory are so dire that it is hard to imagine we would go quite that far down that path.”
“This is a problem we can solve,” Breitburg said. “Halting climate change requires a global effort, but even local actions can help with nutrient-driven oxygen decline.”
She pointed to recoveries in Chesapeake Bay in the US and the Thames river in the UK, where better farm and sewage practices led to dead zones disappearing.

However, Prof Robert Diaz at the Virginia Institute of Marine Science, who reviewed the new study, said: “Right now, the increasing expansion of coastal dead zones and decline in open ocean oxygen are not priority problems for governments around the world. Unfortunately, it will take severe and persistent mortality of fisheries for the seriousness of low oxygen to be realised.”

The oceans feed more than 500 million people, especially in poorer nations, and provide jobs for 350 million people.
But at least 500 dead zones have now been reported near coasts, up from fewer than 50 in 1950.
Lack of monitoring in many regions means the true number may be much higher.

The open ocean has natural low oxygen areas, usually off the west coast of continents due to the way the rotation of the Earth affects ocean currents.
But these dead zones have expanded dramatically, increasing by millions of square kilometres since 1950, roughly equivalent to the area of the European Union.


Low-oxygen zones are spreading around the globe.
Red dots mark places on the coast where oxygen has plummeted to 2 milligrams per liter or less, and blue areas mark zones with the same low-oxygen levels in the open ocean.
(GO2NE working group. Data from World Ocean Atlas 2013 and provided by R. J. Diaz)
Furthermore, the level of oxygen in all ocean waters is falling, with 2% – 77bn tonnes – being lost since 1950.
This can reduce growth, impair reproduction and increase disease, the scientists warn.
One irony is that warmer waters not only hold less oxygen but also mean marine organisms have to breathe faster, using up oxygen more quickly.

There are also dangerous feedback mechanisms.
Microbes that proliferate at very low oxygen levels produce lots of nitrous oxide, a greenhouse gas that is 300 times more potent than carbon dioxide.

Beautiful colours of an algae bloom off the coast of the Falklands towards the end of 2017
captured by OLCI on Sentinel-3

In coastal regions, fertiliser, manure and sewage pollution cause algal blooms and when the algae decompose oxygen is sucked out of the water.
However, in some places, the algae can lead to more food for fish and increase catches around the dead zones.
This may not be sustainable though, said Breitburg: “There is a lot of concern that we are really changing the way these systems function and that the overall resilience of these systems may be reduced.”

 Projected oxygen concentration changes at 200-600 meters’ depth in the oceans, comparing model projections for 2090-2099 to 1990-1999. Bopp, L., L. Resplandy, J.C. Orr, S.C. Doney, J.P. Dunne, M. Gehlen, P. Halloran, C. Heinze, T. Ilyina, R. Séférian, J. Tjiputra, and M. Vichi. 2013, CC BY

The new analysis was produced by an international working group created in 2016 by Unesco’s Intergovernmental Oceanographic Commission.
The commission’s Kirsten Isensee said: “Ocean deoxygenation is taking place all over the world as a result of the human footprint, therefore we also need to address it globally.”

Lucia von Reusner, campaign director of the campaign group, Mighty Earth, which recently exposed a link between the dead zone in the Gulf of Mexico and large scale meat production, said: “These dead zones will continue to expand unless the major meat companies that dominate our global agricultural system start cleaning up their supply chains to keep pollution out of our waters.”

Diaz said the speed of ocean suffocation already seen was breathtaking: “No other variable of such ecological importance to coastal ecosystems has changed so drastically in such a short period of time from human activities as dissolved oxygen.”
He said the need for urgent action is best summarised by the motto of the American Lung Association: “If you can’t breathe, nothing else matters.”

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